Q. When Ethane-1,2-diamine is added progressively to an aqueous solution of Nickel (II) chloride, the sequence of colour change observed will be :
A) Violet $\to$ Blue $\to$ Pale Blue $\to$ Green
B) Pale Blue $\to$ Blue $\to$ Green $\to$ Violet
C) Green $\to$ Pale Blue $\to$ Blue $\to$ Violet
D) Pale Blue $\to$ Blue $\to$ Violet $\to$ Green
Explanation
[Solution by Dr. Abubacker] $[Ni(H_2O)_6]^{2+}$ (green) $\to[Ni(en)(H_2O)_4]^{2+}$ (pale blue) $\to[Ni(en)_2(H_2O)_2]^{2+}$ (blue) $\to[Ni(en)_3]^{2+}$ (violet). Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.